Generally, a receiver has a decoder function to decode content data and output it as a video signal or an audio signal to various devices (for example, a speaker) (for example, refer to Patent Document 1). Moreover, the receiver also has an amplifier function to amplify the audio signal, a selector function to change over a target to which video or audio is input and output, and a correction function to adjust a frequency characteristic or the like of the audio signal.
FIG. 1 is a block diagram showing a configuration of a receiver 1200 in a related art. The receiver 1200 includes an input unit 1021, a decoder 1022, a sound processing DSP 1023, a CPU 1024, a communication unit 1025, a ROM 1026, a RAM 1027, a D/A conversion unit 1028, and an amplifying unit (AMP) 1029.
The input unit 1021 functionally includes an HDMI (High Definition Multimedia Interface) (registered trademark) receiver 1210, a DIR (Digital audio Interface Receiver) 1211, and an A/D conversion unit 1212.
The DIR 1211 receives an input of a digital audio signal (a signal conforming to the standard of S/PDIF) from a player 1300 (refer to FIG. 2), and outputs the signal to the decoder 1022. The A/D conversion unit 1212 receives an input of an analog audio signal. The A/D conversion unit 1212 converts the analog audio signal into a digital audio signal, and outputs it to the decoder 1022. The HDMI receiver 1210 receives an HDMI signal from the player 1300 (refer to FIG. 2).
FIG. 2 shows an input and output relation of various signals in the HDMI. The HDMI receiver 1210 uses a DDC (Display Data Channel) signal So of the HDMI to output processable information (EDID: Extended Display Identification Data) indicating a processable signal by the own device to the player 1300. Moreover, the receiver 1210 receives the HDMI signal from the player 1300. The HDMI signal includes an audio signal (a compressed audio signal) Sn11, a control signal Sn12, a video signal Sn2, a horizontal synchronization signal Sn31, a vertical synchronization signal Sn32, and a pixel and clock Sn4. The HDMI has a CEC (Consumer Electronics Control) line L11 for performing complicated control between devices, and an HPD (Hot-Plug-Detect) line L12 for detecting whether the device is in a connected state or in a disconnected state. A decoder 1222 outputs the decoded video signal Sn2, the horizontal synchronization signal Sn31, the vertical synchronization signal Sn32, and the pixel and clock Sn4 to an external display device. A packet processing unit 1301 of the player 1300 packetizes the audio signal Sn11 and the control signal Sn12. An encoder 1302 synchronizes the video signal Sn2 with the packetized audio signals and the packetized control signals to perform encoding to three data signals Sp1 to Sp3 and one clock signal Sp4. A packet processing unit 1221 extracts the packetized compressed audio signals and control signals from the HDMI signal received by the decoder 1222, and performs processing to restore the packetized compressed audio signals and control signals to the compressed audio signal Sn11 and control signal Sn12. The restored compressed audio signal Sn11 and control signal Sn12 are output to the decoder 1022.
The decoder 1022 includes a DSP (Digital Signal Processor). The decoder 1022 decompresses the compressed audio signal to decode it to a multichannel audio signal. The decoder 1022 also performs processing to extend, for example, a stereo-channel audio signal to a multichannel audio signal such as 5.1 channel. The decoder 1022 outputs the generated audio signal to the sound processing DSP 1023.
The sound processing DSP 1023 performs predetermined sound processing on the audio signal. For example, the sound processing DSP 1023 adjusts the audio signal so as to be in an optimum sound field environment suitable for a listening position, by adjusting the frequency characteristic or the like.
The D/A conversion unit 1028 converts the audio signal having been subjected to the sound processing, into an analog audio signal. The amplifying unit 1029 amplifies the analog audio signal and outputs the amplified signal to the speaker.
In such a receiver 1002, the CPU 1024 reads out firmware stored in the ROM 1026, to the RAM 1027 being a work memory, and causes the decoder 22 and the sound processing DSP 1023 to execute various processing as described above.
The receiver 1002 receives the new firmware via the communication unit 1025 to update the firmware in the ROM 1026. According to such processing, the receiver 1002 can realize new signal processing.